When producing liquids, such as for example drilling fluid, large volumes of fine graded material, such as powder, and a suitable liquid are mixed. The mixing of fine graded material into a liquid requires large shear forces in order to obtain the required quality of mixture.
U.S. Pat. No. 4,765,540 discloses a process and an apparatus for generating a plurality of helically shaped converging or diverging fluid flows, and where a particle shaped material is added to said flow, downstream of the nozzles, said particles being introduced into the fluid flow in such way that the particles are distributed over a large area. The purpose of the solution according to U.S. Pat. No. 4,765,540 is to use the fluid containing particles as an abrasive medium to abrade or cut through a material, such as very hard materials such as concrete, rock, glass or metal.